Pulse rate calculating apparatus

Abstract: A pulse counting apparatus which has a simple structure and makes few count errors. When the number of pulses at a wrist or the neck of the user counted by means of palpation amounts to 10 and the user stops by using an S1 key the measurement of the pulse counting time period in a timer (T), it is determined whether the pulse counting time period is 3 seconds or less (FIG. 4, step S41). If the time period is 3 seconds or less, it is determined that the pulse is miscounted, the value of the timer (T) is cleared (step S42) and "1" is set in a flag (G). As a result, the apparatus is switched to a measurement mode. If the time period exceeds 3 seconds (step S41), pulse per minute is calculated from the time period and the number of the pulses (step S44) 10. An exercise intensity corresponding to the pulse is calculated from the pulse and the set age of the user (step S45). The pulse and the exercise intensity is displayed in a display (8).

Description: The present invention relates to a pulse rate calculating apparatus according to the subject matter of claim 1. Conventionally, in medical facilities, an electrocardiographic signal or pulse generated when the heart contracts is detected by a sensor, and an apparatus for displaying a waveform of the detected signal and an apparatus for calculating the pulse per minute from the signal detected by the sensor and displaying the pulse have been used. However, since these apparatuses are large and expensive, there has been a demand for a portable pulse counting apparatus, which is inexpensive and which thus allows personal use. In response to the demand, a pulse counting apparatus having a sensor for counting a pulse, applicable to a small apparatus (e.g., a watch), has been put into practice. Such a pulse counting apparatus is disclosed in, for example, U.S. Patents Nos. 4,807,639 and 5,316,008. EP-A-0 556 702 discloses the features of the preamble of claim 1. The aforementioned pulse counting apparatus in the mentioned US-patents, however, has the following drawback. That is, noise is liable to generate in a sensor of the apparatus for detecting an electrocardiographic signal or an optical sensor for detecting pulse. Since noise can result in an inaccurate count, the pulse must be counted repeatedly. The object of, the present invention is to provide a pulse rate calculating apparatus, which has a simple structure and makes few count errors. This object is solved by the subject matter of claim 1. Further advantageous embodiments of the invention are subject matter of the dependent claims. According to the present invention, a pulse rate can be calculated with a very simple structure, without using a pulse sensor. This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: FIG. 1 is a block diagram of a pulse rate calculating apparatus according to the present invention; FIG. 2 is a diagram showing the structure of the RAM shown in FIG. 1; FIG. 3 is a flowchart showing an operation of a pulse rate calculating apparatus according to a first embodiment of the present invention; FIG. 4 is a flowchart showing a calculating operation; FIG. 5 is a diagram for explaining a mode switching operation; FIG. 6 is a diagram showing a state of the display in a time display mode; FIG. 7 is a diagram showing a state of the display in an initial mode of a pulse mode; FIG. 8 is a diagram showing a state of the display in a pulse display mode; FIG. 9 is a flowchart showing an operation of a pulse rate calculating apparatus according to a second embodiment of the present invention; and FIGS. 10A and 10B are diagrams showing states of the display in a pulse rate calculating operation of the second embodiment. Embodiments of the present invention will be described with reference to the accompanying drawings. In the embodiments, the pulse rate calculating apparatus of the present invention is applied to an electronic watch having a pulse counting function. FIG. 1 is a diagram showing the structure of the electronic watch having the pulse rate calculating function. Referring to FIG. 1, an oscillation clock signal of a predetermined frequency generated in an oscillator 1 is divided by a frequency divider 2. A frequency-divided signal is input to a control unit 3. A key input section 4 has a SW1 key for switching modes such as a time display mode and a pulse mode, a SW2 key for starting and stopping measurement of a pulse counting time, a SW3 key for inputting the age of the user and a SW4 key for switching the pulse mode to an age setting mode (to be described later) in which an input of the age by means of the S3 key is permitted. The control unit (central processing unit) 3 executes a key process, a time-counting process, a pulse calculation process (to be described later), and the like, in accordance with a control program stored in a ROM (read only memory) 5, and stores a measured time and a calculation result in a RAM (random access memory) 6. The control unit 3 reads time data or pulse data (to be described later) from the RAM 6, outputs them to a driver 7 and displays them in a display unit 8 such as a liquid crystal display. The structure of the RAM 6 will now be described with reference to FIG. 2. A display register 21 stores display data to be displayed in the display unit 8. A time register 22 stores current time data. A mode register M stores numerals corresponding to operation modes: "0" in the time display mode, "1" in the pulse mode and "2" in a recall mode in which pulse data is read from a data memory 26 (to be described later). A flag F is to distinguish between a pulse count mode and the age setting mode. More specifically, "0" is set to the flag F in the pulse count mode and "1" is set in the age setting mode. As regards a flag G, "1" is set when a pulse counting time is measured and "0" is set in the other situations. A timer (a time measuring means) T measures a time period in which the user counts a predetermined number (e.g., 10) of pulses by means of palpation. An age register 23 stores age data input by the user. A pulse register 24 stores the number of pulses per minute calculated from an equation based on the period of time measured by the timer T and a predetermined number of pulses. An intensity register 25 stores exercise intensity data calculated by an exercise intensity calculation process (to be described later) based on a maximum number of pulses, depending on the age, and the number of pulses obtained by the calculation (pulse data stored in the pulse register 24). The exercise intensity data indicates a percentage with respect to the intensity of exercise corresponding to the maximum pulse of the set age. A data memory 26, comprised of a plurality of memory areas, stores the calculated pulse data in order. An operation of the above embodiment will be described with reference to the flowcharts shown in FIGS. 3 and 4 and the diagram shown in FIG. 5 for explaining the operation modes. When the control unit 3 is in a halt state in a step S1 as shown in FIG. 3, if it detects a timing signal output from the frequency-divider 2, it executes a time counting process of a step S2. If it detects a key operation signal, the flow proceeds to a step S9. If a timing signal is detected in the step S1, a time counting process of the step S2 is executed. In the time counting process, current time data stored in the time register 22 is updated. Subsequently, in a step S3, it is determined whether the content of the mode register M is "1" (M=1) and the content of the register F is "0" (F=0). If M ≠ 1 or F ≠ 0 in the step S3, the flow proceeds to a step S8 in which a display process in the corresponding mode is performed. For example, if the operation mode is the time display mode (M=1), the time data stored in the time register 22 is transferred to the display register 21, so that the current date and time are displayed on the display unit 8. If M=1 and F=0 in the step S3, that is, if the current operation mode is the pulse mode and not the age setting mode, the flow proceeds to a step S4 in which it is determined whether the flag G is "1". In the step S4, if the flag G is "1", that is, if the pulse counting time is being measured, the flow proceeds to a step S5 in which the value of the timer T for measuring the pulse counting time is incremented by 1. In the next step S6, it is determined whether the value of the timer T amounts to "20", i.e., whether the counting time period amounts to 20 seconds. In the step S6, if the counting time period amounts to 20 seconds, the values of the timer T and the flag G are cleared in a step S7, so that the operation mode is switched to the initial mode. Thereafter, the display process is executed in a step S8, so as to display the counting time period "0" of the timer T. The reason, why the timer T and the flag G are cleared in the step S7 if the value of the timer T amounts to 20 seconds, will be described. In this embodiment, the timer T measured a pulse counting time period in which the number of pulses becomes 10, and calculates pulse per minute from the pulse counting time period. More specifically, assuming that the number of pulses to be counted is X, if a pulse counting time T elapses until the pulses amount to X, the pulse per minute Y is obtained by the equation: Y=60X/T . In the apparatus of the embodiment, since the pulse counting time is a period of time which elapses until the pulses amount to X (10), the numerical data of 60 × 10=600 is prestored in the ROM 5, so that the pulse per minute is obtained by the calculation "600/Pulse Counting Time". However, if the pulse counting time of 20 seconds elapses until the pulses amount to 10, the pulse per minute will be 30. Actually, however, the pulse per minute cannot be so low. Therefore, when the value of the timer T becomes 20, the control unit determines that the pulse is miscounted and clears the values of the timer T and the flag G, so that the pulse cannot be calculated from the value of the timer T. In the step S6, if the value of the timer T is less than 20 seconds, the flow proceeds to the step S8 in which the counting time of the timer T is displayed on the display unit 8. If a key operation signal is detected in the step S1, the flow proceeds to the step S9, in which it is determined whether the SW1 key is operated. If the SW1 key is operated, the flow proceeds to a step S10, in which the value of the mode register M is incremented by 1, thereby changing the operation mode. Subsequently, the display process of step S8 is executed, so that a display process in the corresponding mode is performed. In the step S9, if a key other than the SW1 key is operated, the flow proceeds to a step S11, in which it is determined whether the SW2 key is operated. If the SW2 key is operated, the flow proceeds to a step S12, in which it is determined whether the value of the mode register M is "1" and the value of the flag F is "0". In the step S12, if M=1 and F=0, the flow proceeds to a step S13, in which it is determined whether the flag G is "0". In the step S13, if the flag G is "0", i.e., if the SW2 key is operated in the initial mode of the pulse mode, the flow proceeds to a step S14, in which the flag G is set to "1" and the mode is switched to a pulse count time measurement mode, so as to start the measurement of the pulse counting time in the timer T. Thereafter, the display process of the step S8 is executed to display the pulse counting time in the timer T. If the flag G is "1" in the step S13, i.e., if the SW2 key is operated while the pulse counting time is being measured, the flow proceeds to a step S15, in which the flag G is set to "0" and the current operation mode is switched to a pulse display mode and the measurement of the pulse counting time of the timer T is stopped. At the same time, the calculation in a step S16 is executed. The calculation process executed in the step S16 will now be described with reference to the flowchart of FIG. 4. First, in a step S41, it is determined whether the value of the timer T, when the measurement is stopped, is 3 second or less. If the period of time in which the pulses amount to 10 is 3 seconds or less, the pulse per minute will be 200 or greater. Since, in general, the pulse per minute cannot be so much, the control unit determines that the pulse is miscounted by the user and clears the value of the timer T in a step S42. Further, in step S43 is set to the flag G, so that the operation mode is switched to the measurement mode. If in the step S41, the value of the timer T exceeds 3 seconds, the pulse is calculated in a step S44, i.e., the calculation "600/Pulse Counting Time" (the period of time measured by the timer T until the pulses amount to 10) is executed so as to obtain the pulse per minute. Further, in a step S45, intensity of exercise is calculated from the age data stored in the age register 23 and the pulse data calculated in the step S44. There is a relationship between the age of a person and his or her maximum pulse. That is, the maximum pulse of a person of an age is represented by "220-Age". In the aforementioned calculation of the exercise intensity, assuming that the exercise of the intensity "100" results in the maximum pulse, the intensity of the exercise, corresponding to the calculated pulse, is obtained from the ratio of the calculated pulse to the maximum pulse. For example, the maximum pulse of a person of 20 years old is 220-20=200. In this case, if the pulse of the person is 180 when he or she performs an exercise, the intensity of the exercise is (180/200) × 100=90%. When the calculation of the pulse and the exercise intensity has completed, the calculated pulse data is stored in the data memory 26 in a step S46. Mode switching by means of the SW1 key and SW2 keys will be described with reference to FIG. 5. In the time display mode in which M=0, when the SW1 key is operated, "1" is set to the mode register M, the apparatus is switched to the pulse mode. Immediately after the mode is switched to the pulse mode, "0" is set to the flag G and the apparatus is set in the initial mode as indicated by A in FIG. 5. In this state, when the SW2 key is operated, "1" is set to the flag G and the apparatus is set in the measurement mode as indicated by B in FIG. 5, at which time, a time measurement operation of the timer T is started. If the SW2 key is operated within 3 seconds of the start of the time measurement operation of the timer T, the measured time is cleared and the measurement operation is performed again. If the SW2 key is not operated in 20 seconds, the apparatus is returned to the initial mode. If the SW2 key is operated in 3 to 20 seconds after the start of the time measurement operation, "0" is set to the flag G and the apparatus is set in the pulse display mode and the time measurement operation of the timer T is stopped. In the pulse display mode, the pulse per minute and the exercise intensity are calculated from the time measured by the timer T and the predetermined number of ten pulses and displayed in the display 8. In the pulse mode in which M=1, when the SW1 key is operated, the value of the mode register M is changed to "2", i.e., the apparatus is switched to the recall mode. In the recall mode, the pulse data stored in the data memory 26 can be successively displayed by operating the SW3 key. FIGS. 6 to 8 show states of the display in the time display mode, the initial mode and the pulse display mode. FIG. 6 shows a state of the display in the time display mode, indicating the current date and time, October 15, 10:25 35". FIG. 7 shows a state of the display in the initial mode, indicating the letters "PULSE" and the initial value "0:00" of the timer. FIG. 8 shows a state of the display in the pulse display mode, indicating the pulse per minute "120" and the exercise intensity "65%" calculated from the pulse and the age. Referring to FIG. 3 again, in the step S11, if the SW2 key is not operated, the flow proceeds to a step S17, in which it is detected whether the SW3 key is operated. If the SW3 key is operated, it is determined whether the value of the mode register M is "1" in a step S18. If the SW3 key is operated in the pulse mode (M=1), it is determined whether the flag F is "1" in a step S19. If "YES" in the step S19, i.e., if the SW3 key is operated in the age setting mode in which M=1 and F=1,, the flow proceeds to a step S20, in which the value of the age register 23 is incremented by 1. If the flag F is not "1" in the step S19, i.e., if the SW3 key is operated in the pulse mode in which F=0, the flow proceeds to a step S21 in which it is determined whether the flag G is "0". If the flag G is "0" in the step S21 (i.e., if the SW3 key is operated in the pulse display mode), the timer T and the pulse register 24 are cleared in a step S22 and the apparatus is returned to the initial mode. If the value of the mode register M is not "1" in the step S18, the flow proceeds to a step S23 in which it is determined whether the value of the mode register M is "2". If M=2, i.e., if the apparatus is in the recall mode, the read address in the data memory 26 is increased in a step S24. In other words, in the recall mode, the pulse data stored in the data memory 26 can be successively displayed by operating the SW3 key. It is possible that the step S24 includes a process of calculating the exercise intensity from the read pulse data and the age data read from the age register 23 and displaying the calculated intensity. The function of the SW3 key will be described with reference to FIG. 5. In the age setting mode (M=1, F=0), each time the SW3 key is operated, the value of the age register 23 is incremented by 1. Thus, the age of the user can be set by operating the SW3 key in the age setting mode. When the SW3 key is operated in the pulse display mode (M=1, F=0, G=0), the timer T and the pulse register 24 are cleared and the apparatus is switched to the initial mode. When the SW3 key is operated in the recall mode (M=2), the pulse data stored in the data memory 26 are successively read out. Referring to FIG. 3 again, if the SW3 key is not operated in the step S17, the flow proceeds to a step S25 in which it is determined whether the SW4 key is operated. If the SW4 key is operated in the step S25, it is determined whether the value of the mode register M is "1" in a step S26. If M=1, it is determined whether the flag F is "0" in a step S27. If F=0 in the step S27, i.e., if the SW4 key is operated in the pulse mode, "1" is set in the flag F in a step S28, thereby switching the apparatus to the age setting mode. If F=1 in the step S27, i.e., the SW4 key is operated in the age setting mode, the flow proceeds to a step S29 in which "0" is set to the flag F thereby switching the apparatus to the pulse mode. If the SW4 key is not operated in the step S25, the flow proceeds to a step S30, so that another key operation can be executed. A mode switching process by means of operating the SW4 key will be described with reference to FIG. 5. As shown in FIG. 5, when the SW4 key is operated in the pulse mode (M=1, F=0), the apparatus is switched to the age setting mode. In the age setting mode, a desired age can be set by operating the SW3 key as described above. When the SW4 key is operated in the age setting mode (F=1), "0" is set to the flag F and the apparatus is switched to the initial mode of the pulse mode. In the pulse mode, the pulse counting time period can be measured by operating the SW2 key as described above. In this embodiment, as described above, when the period of time, in which the pulses amounts to a predetermined number, is measured, if the measured period of time is too short (shorter than a first reference period of time, e.g., 3 seconds in the embodiment) in a logical sense or too long (longer than a second reference period of time, e.g., 20 seconds in the embodiment), the measured period of time is invalidated. In this way, even if the user miscounts pulse, the miscounted pulse is not displayed. A second embodiment of the present invention will now be described with reference to FIGS. 9, 10A and 10B. In an operation of the second embodiment, after the time measurement operation by the timer T starts in the pulse mode, pulse per minute is calculated in every second based on the period of time measured by the timer T and the predetermined number of pulses (e.g., 10 pulses in the embodiment) and the calculated pulse is displayed. In the following, only portions different from those of the first embodiment shown in FIG. 3 will be described. FIG. 9 is a flowchart showing processes of the second embodiment inserted between the steps S5 and S6 of the flowchart of FIG. 3. After the timer is incremented by 1 in the step S5, it is determined whether a second carry is generated in a step S51. If a second carry is generated, a calculation of pulse and intensity is executed in a step S52. The calculation is the same as the calculation of pulse in the step S44 and the calculation of intensity in the step S45 shown in FIG. 4. That is, pulse per minute is calculated from the value of the timer T and the number (10) of pulses and the exercise intensity is calculated from the pulse per minute and the age. Thereafter, in the step S6, it is determined whether the timer T accounts to 20 seconds. The subsequent steps are the same as those shown in FIG. 3. FIG. 10A shows a display when 5 seconds have elapsed from the start of the measurement of the pulse counting time. In this case, since the pulse amounts to 10 in 5 seconds, the pulse per minute "120" is displayed. Further, since the user is 20 years old in this case, the exercise intensity is calculated by the equation (120/200) × 100=60 and the calculation result "60" % is displayed. FIG. 10B shows a display when 6 seconds have elapsed from the start of the measurement of the pulse counting time. In this case, since the pulse amounts to 10 in 6 seconds, the pulse per minute "100" is displayed. Further the exercise intensity "50" % is obtained and displayed. In the second embodiment, the pulse per minute is calculated and displayed every second after the start of the measurement of the pulse counting time. Therefore, the number displayed when the user amounts 10 pulses is the pulse per minute of the user. It is thus unnecessary to stop the measurement of the period of time. In the above embodiments, the pulse per minute is obtained by the calculation "600/Pulse Counting Time". However, the number of pulses to be counted is not limited to 10 but can be 5, 20 or any other number and the calculation can be modified accordingly. Further, it is possible that a table data of pulse per minute corresponding to the pulse counting time is stored in the ROM, so that the data in accordance with the time can be read. In this case, the calculation is not required. Moreover, the present invention is not limited to the watch as used in the above embodiments but can be applied to any other device having a time measuring function. As has been described above, the present invention has the following advantages. First, pulse per unit time can be immediately obtained simply by counting the number of pulses at a wrist or the neck of the user by means of palpation and measuring the period of time in which the pulses amount to a predetermined number. Further, if the measured period of time is too short or long, the period is invalidated, so that an incorrect pulse cannot be displayed. Furthermore, since the intensity of exercise is displayed along with the pulse, the user can see the degree of the exercise.

Claims: A pulse rate calculating apparatus comprising: time measuring means (T) providing time data for producing a period of time during which a predetermined number of pulses are to be counted by the user; numerical data storing means (5) for storing predetermined numerical data; calculating means (S16) for obtaining pulse data representing the number of pulses per minute on the basis of the predetermined numerical data stored in the numerical data storing means and the time data produced by the time measuring means (T); and display means (8) for displaying the pulse data obtained by the calculating means, and manual operation switch means (SW2) operable for starting or stopping the time measuring means (T), to produce the time period during which the predetermined number of pulses are counted by the user, characterized by control means (S6, S7) for automatically stopping the time measuring performed by the time measuring means (T), if the time since the manual operation switch means started the time measuring exceeds a predetermined time. The pulse rate calculating apparatus according to claim 1, characterized in that the numerical data storing means stores as numerical data 60 times the number of pulses to be counted by the user, and the calculating means includes means (S44) for dividing the numerical data by the time data and outputting a calculation result as the data representing the pulses per minute. The pulse rate calculating apparatus according to claim 2, characterized in that the calculating means performs the calculation of the pulse rate once every second whilst the time measuring means is operating. The pulse rate calculating apparatus according to one of claims 1 to 3, characterized in that the calculating means obtains the data representing the pulses per minute once every second whilst the time measuring means is operating. The pulse rate calculating apparatus according to one of claims 1 to 4, characterized by further comprising: age data storing means (23) for storing age data; and exercise intensity calculating means (S45) for calculating exercise intensity data from the age data stored in the age data storing means and the pulse data obtained by the calculating means. The pulse rate calculating apparatus according to one of claims 1 to 5, characterized by further comprising: restarting means (S41, S42, S43) for automatically restarting the time measuring performed by the time measuring means by clearing the time measured by the time measuring means when the time measuring is stopped by the manual operation switch means and the time measured by the time measuring means is less than a predetermined time.

Inventors: SUGA FUSAO, SUGA, FUSAO, Suga, Fusao, c/o Hamura R &amp; D Center
Applicants: CASIO COMPUTER CO LTD, CASIO COMPUTER CO., LTD.
Application year: 1994
Main classification: A61B5
IPC codes: A61B5, G04G99